U4-7847 Do not allow folders to be created underneath content types (or data types)

src/Umbraco.Web.UI.Client/src/views/documenttypes/create.controller.js

@@ -9,6 +9,7 @@
 function DocumentTypesCreateController($scope, $location, navigationService, contentTypeResource, formHelper, appState, notificationsService, localizationService) {
 
     $scope.model = {
+        allowCreateFolder: $scope.dialogOptions.currentNode.parentId === null || $scope.dialogOptions.currentNode.nodeType === "container",
         folderName: "",
         creatingFolder: false,
     };

src/Umbraco.Web.UI.Client/src/views/documenttypes/create.html

@@ -20,7 +20,7 @@
                 <span class="menu-label"><localize key="create_documentTypeWithoutTemplate"></localize></span>
               </a>
             </li>
-            <li>
+            <li ng-if="model.allowCreateFolder">
                 <a href="" ng-click="showCreateFolder()">
                     <i class="large icon-folder"></i>
                     <span class="menu-label"><localize key="general_folder"></localize></span>